Every Wednesday, EA Sports will update their Team of the Week that you can see in the HUT menu when you load it up.
Once the Team of the Week is updated, EA will put cards in packs that you can buy, or you can save up your coins and buy them on the market. You can test your luck obviously in the packs, or you can play the market to get one as cheap as you can get.
When you get one, the achievement will pop.
EDIT: To be clear for non-returning players, TOTW cards are Black with gold lettering.
There are other types of cards that WON'T work:
Black with grey lettering are Legend players.
Green are Flashback cards
Blue with white zig-zag's are Jr. Flashback cards.
There will be other types of cards as well coming through the year that won't count either. Like Player of the Game, Movember, Hockey Fights Cancer, etc., so make sure if you're specifically going for this achievement, it's Black with Gold lettering.